UnmaintainedUpgrade Reminder
0.1

XenForo doesn't send out reminders letting users know if their account upgrades are due for renewal. If you use the auto-renewal option, that's not a big deal.

This little add-on makes a cron job that sends an email letting users know their upgrade will be expiring in three days and provides a link to the account upgrades page.

After install, double-check your cron schedule to make sure it runs at an appropriate time.

Couple of small issues:

The html version of the email isn't particularly "pretty". I don't care enough to fix it up, but you might.

XenForo won't let you renew an active upgrade. You have to wait until it expires. Nataan's "Advanced User Upgrades" will allow users to extend active upgrades. Other add-ons may offer similar functionality, but this is what I use. Alternatively, you could edit the date range in Model.php from =<3 and >2 to =<1, etc.